Welcome, Guest: Register On Nairaland / LOGIN! / Trending / Recent / New
Stats: 3,150,804 members, 7,810,096 topics. Date: Friday, 26 April 2024 at 08:39 PM

Physicists!!! Help Me To Derive This Equation. - Science/Technology - Nairaland

Nairaland Forum / Science/Technology / Physicists!!! Help Me To Derive This Equation. (1865 Views)

Physicists Lounge / Physicists/Science People...lets Discuss This. / Physicists Or Engineers (2) (3) (4)

(1) (Reply) (Go Down)

Physicists!!! Help Me To Derive This Equation. by Nobody: 11:10pm On May 08, 2015
So . . . I'm an amateur inventor . . . and recently I was trying to build something and I just needed this equation to continue. I've been searching for a long time now and I've even asked some people but none seems to know it. I even tried to derive of with newton's laws but to no avail. Here it is.



suppose we have a mass M, located at a height H above the earth's surface, what equation can be used to find the power P required to keep it there?

Trust me, the above is not as easy as it looks. Please, if you do find it, explain the procedure well abeg. And if there are any constants or values, please indicate.

Thanks in advance. grin wink
Re: Physicists!!! Help Me To Derive This Equation. by Besea(f): 11:55pm On May 08, 2015
Power = mhg/ t t is time
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 12:59am On May 09, 2015
Besea:
Power = mhg/ t t is time
abeg no. That's not it.

The change in height h is zero. If you insert zero into that equation, it destroys everything.

Mgh/t is the equation to find the power required to bring the mass to that height. Not keep it there. Hope you grab? smiley smiley
Re: Physicists!!! Help Me To Derive This Equation. by saintneo(m): 2:46am On May 09, 2015
Potential Energy in the object = MgH
Kinetic Energy if the object falls = .5Mv2 (v - velocity)

v2 = u2 +2gh (h is the height travelled, u = 0)
=> v2 = 2gh

This implies that v changes depending on the height
KE = 2M(gh)2
PE = Mg(H-h)
Total energy is always constant = KE+PE
= 2M(gh)2 + Mg(H-h)
= MgH + 2M(gh)2 - Mgh
Power = dE/dt ( the only variable in the total energy equation is h)
Power = (4Mg2h - Mg)dh/dt


This is complicated. The power derived is the power required to push the object of mass M to the height H.

This implies that if the object is already on the ground, then h=H and if the object is at height H then h=0
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 3:45pm On May 09, 2015
Am an inventor too, though above amateur,,,,Not quite sure, but let me drop my little contribution


mechanical power P,= FV(force *velocity)

and V(escape velocity) = root(2gr)
r=radius of the earth I.e 6378.137 km

P= F * root(2gr).......(escape power I.e power required to escape the earth)

since Mgh/t = power to get to the height H

power to keep the body at that height
= escape power - power to get to that height

= MgH/t - F * root(2gr)....
.......take this with a pinch of salt/Origin grin
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 10:47am On May 11, 2015
IwillLaff:
Am an inventor too, though above amateur,,,,Not quite sure, but let me drop my little contribution


mechanical power P,= FV(force *velocity)

and V(escape velocity) = root(2gr)
r=radius of the earth I.e 6378.137 km

P= F * root(2gr).......(escape power I.e power required to escape the earth)

since Mgh/t = power to get to the height H

power to keep the body at that height
= escape power - power to get to that height

= MgH/t - F * root(2gr)....
.......take this with a pinch of salt/Origin grin
grin . . . i'm coming.
Re: Physicists!!! Help Me To Derive This Equation. by tpiadotcom: 3:33am On Jun 02, 2015
Teempakguy:
abeg no. That's not it.

The change in height h is zero. If you insert zero into that equation, it destroys everything.

Mgh/t is the equation to find the power required to bring the mass to that height. Not keep it there. Hope you grab? smiley smiley

you are trying to hard to sound smart, its not working.

why not do some better things with your time instead of being on nairaland 24/7.
Re: Physicists!!! Help Me To Derive This Equation. by tpiadotcom: 3:34am On Jun 02, 2015
btw, no plane crashes plz.


if you want to be a terrorist, find the balls to move to whichever country they're currently in.

stop being an online wannabee.
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 3:48am On Jun 02, 2015
tpiadotcom:


you are trying to hard to sound smart, its not working.

why not do some better things with your time instead of being on nairaland 24/7.
You do not know the amount of time I spent trying to derive this equation. The amount of used sheets I threw in the waste bin. The amount of chalk dust I choked on, the amount . . . . of sleepless nights I had trying to figure it out. You . . . review the entire thread and decide that I am a . . . wannabe . . . you think I . . . am trying to sound smart, to whom? Who am I trying to impress? Who are you?
My goals are beyond your understanding. I'm not your average person. Just because I uploaded my real picture and not that of a skeleton, does not give you the right to insult me. I am very sure you don't even understand what the question is or you wouldn't have posted the above. Listen, I don't do e-fights anymore so, whenever you see my posts, try not to comment. It's obvious we won't get along much. Thanks.

2 Likes

Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 3:51am On Jun 02, 2015
tpiadotcom:
btw, no plane crashes plz.


if you want to be a terrorist, find the balls to move to whichever country they're currently in.

stop being an online wannabee.
terrorist? undecided

Why would anyone conclude that from this whole thread? undecided undecided undecided
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 11:20am On Jun 03, 2015
@op
Please Pay no mind to those who are trying to derail your thread With their badbelle.
Oboy this your question really tough o
Am here to learn from the masters
Nice educative thread keep it up
Re: Physicists!!! Help Me To Derive This Equation. by soldierdollar(m): 7:37am On Jun 04, 2015
Since there is no relative motion , it means the object is at rest . Therfore , no work is done ... Mgh or force X distance is zero smiley
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 1:30am On Jun 13, 2015
Timflex:
@op
Please Pay no mind to those who are trying to derail your thread With their badbelle.
Oboy this your question really tough o
Am here to learn from the masters
Nice educative thread keep it up
thanks man. smiley
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 1:31am On Jun 13, 2015
saintneo:
Potential Energy in the object = MgH
Kinetic Energy if the object falls = .5Mv2 (v - velocity)

v2 = u2 +2gh (h is the height travelled, u = 0)
=> v2 = 2gh

This implies that v changes depending on the height
KE = 2M(gh)2
PE = Mg(H-h)
Total energy is always constant = KE+PE
= 2M(gh)2 + Mg(H-h)
= MgH + 2M(gh)2 - Mgh
Power = dE/dt ( the only variable in the total energy equation is h)
Power = (4Mg2h - Mg)dh/dt


This is complicated. The power derived is the power required to push the object of mass M to the height H.

This implies that if the object is already on the ground, then h=H and if the object is at height H then h=0
I think this requires knowledge of partial differentiation.
Am I right?
Re: Physicists!!! Help Me To Derive This Equation. by saintneo(m): 3:57am On Jun 13, 2015
Teempakguy:
I think this requires knowledge of partial differentiation.
Am I right?

Just differentiation, there is only one variable involved
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 6:16am On Jun 13, 2015
saintneo:


Just differentiation, there is only one variable involved
mass is also a variable.
Re: Physicists!!! Help Me To Derive This Equation. by saintneo(m): 7:45am On Jun 13, 2015
Teempakguy:
mass is also a variable.

In my analysis, I assumed mass to be constant.


But if mass is varying, then the equations will definitely change and partial differentiation will be applicable.
Re: Physicists!!! Help Me To Derive This Equation. by Nobody: 7:58am On Jun 13, 2015
saintneo:


In my analysis, I assumed mass to be constant.


But if mass is varying, then the equations will definitely change and partial differentiation will be applicable.
thanks, I just wanted to clear that up. smiley
Re: Physicists!!! Help Me To Derive This Equation. by beatsbyj2g(m): 10:44pm On Jun 14, 2015
Let's say d object is at a point H above the ground.......
Naturally d object if left a lone will fall back to the earth with a force of

F=mass*accl due. To gravity

So in othe to keep the object floating u will need a resultant force equal to the one above (f=m*g)

To find power now
Power =force to keep it floating * H /time

(1) (Reply)

Badoo Registration Www.badoo.com Bodoo Sign Up & Login / The Best Text To Speech Software For Youtube Videos / .

(Go Up)

Sections: politics (1) business autos (1) jobs (1) career education (1) romance computers phones travel sports fashion health
religion celebs tv-movies music-radio literature webmasters programming techmarket

Links: (1) (2) (3) (4) (5) (6) (7) (8) (9) (10)

Nairaland - Copyright © 2005 - 2024 Oluwaseun Osewa. All rights reserved. See How To Advertise. 35
Disclaimer: Every Nairaland member is solely responsible for anything that he/she posts or uploads on Nairaland.